Piezo audion



July 26, 1927. 1,636,921

A. M L. NICOLSON PIEZO AUDION Filed Nov. 11 1926 2 Sheets-Sheet l INVEN TOR.

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ATTORNEY July 26 1927, 1,636,921

A. M L NICOLSON PIEZO AUDION Filed Nov. 11, 1926 2 Sheets-Sheet 2 INVENTOR.

ATTORNE UN s ALEXANDER IlIoLEAN NICOLSON, OF NEW YORK, N. Y., ASSIGNOR TO WIRED RADIO,

INC., OF NEW YORK, N. Y., A CORPORATION OF DELAWARE.

PIEZO AUDION.

Application filed November 11, 1926. Serial No. 147,750.

My invention relates broadly to piezo electric crystal apparatus and more particularly to an apparatus which have entitled The piezo audion.

One of the objects of my invention is to provide a piezo electric crystal apparatus for controlling the condition of an electrical 'circuit in accordance with variations in sound vibrations where the apparatus is of extreme sensitivity and is arranged to modulate the control current at relatively large amplitude.

Another object of my invention is to pro vide a piezo electric crystal apparatus 1n .15 which a quartz or tourmaline crystal having piezo electric properties is mounted within a highly evacuated envelope in immediate association with the elements of an electron tube whereby electric charges acquired by 2 the piezo electric element may be directly impressed upon one or more of the elements of an electron tube.

Another object of m invention is to provide a mounting for an element possessing piezo electric properties in association with the elements of an electron tube whereby a high degree of electrical efficiency may be secured by the cooperation of the piezo elec-- tric element and the electron discharge device.

Other and further objects of my invention will be understood from the specification hereinafter following by reference to the accompanying drawings in which:

Figure 1 represents a side elevation of an electron tube and piezo electric crystal apparatus partially broken away and shown in cross-section illustrating the arrangement of the piezo electric element and the electrodes of-the electron tube device; Fi 2 is a cross-sectional view taken throug the piezo audion on line 2-2 of Fig. 1; Fi 3 shows diagrammatically the piezo an ion fgnnected in a control circuit and illustrat- 45. g the principle of operation of my invention; Fig. 4 shows a modified mounting for a quartz crystal in association with the elements of the tube structure; Fig. 5 indicates .the' manner in which the quartz crystal is '5 cut for mounting as represented in Fig. 4;

and Fig. 6 is an end view of the quartz crystal and its mounting as shown in Fig. 4.

Referring to the drawings in more detail, reference character 1' designates an evacuated envelope for the piezo audion of my invention having a base 2 with pin terminals 3 projecting therefrom for establishing connection with a suitable support or socket. A central press or support 4 is provided for the electrodes of the electron tube device. I have illustrated the filament electrode or cathode by the reference character 5 with an associated grid electrode 6 and cooperating plate or anode 7 mounted in close relationship about the centrally extending rod member 8. The rod member 8. is provided with a recess 9 in its upper extremity in which a contact 10 is seated, the contact 10 being connected directly to the grid element 6. The glass envelope of the electron tube has one wall thereof arranged in the form of a diaphragm against which sound vibrations may impinge.

I have illustrated one of the embodiments of my invention where a metallic dia hragm 11 is introduced within the wall of 1e tube 1 and sealed in position as represented at 14. At the back of the diaphragm 11 I provide a contact 12 for receiving a piezo electric element such as tourmaline as represented at 15 or quartz as represented at 21 in Fig. 4. In Fig. 1 I have represented the contact 12 as connected. with the cathode 5 in such manner that the piezo electric device functions between the grid and filament electrodes. In Fig. 3, however, I have shown a connection brought out from electrode 12 to a series circuit including a source of potential 16 and the cathode 5.

Fig. 3 illustrates-more clearly the circuit arrangement for the piezo audion of my in vention where the cathode 5 is heated from a suitable source 17 and the plate circuit is energized from a suitable source 18 with a winding 19 included in series therewith and inductively coupled to an output circuit including secondary winding 20. v

In Figure 5, I have illustrated the manner in which a quartz crystal 21 may be cut from a natural crystalllne quartz 22 with 100 the ends of the crystal 21 cut off at angles as represented at 23 and 24. Electrodes in the form of platinum films 25 and 26 may be deposited on both faces of the piezo electric crystal 21. Portions of the faces are kept uncoated adjacent opposite ends as represented at 27 and 28 preventing ashort circuit across the faces of the piezo electric crystal element. The pointed ends 23 and 24 may be electrically connected to knobs 29 electric crystal element.

It is not essential that the electrodes actual- 1y contact with. the piezo electric crystal as the electrodes may be positively separated by an air gap from the surfaces of the piezo electric plate, a. capacity connection being effected with the electrodes of the piezo electric crystal element.

. The piezo audion may be employed as a modulating apparatus where sound vibrations impinge directly against one wall of the highly evacuated envelope 1 which is arranged to transmit the vibrations to the piezo electric element or the sound vibrations strike the diaphragm 11 and impart corresponding movement to the piezo electric element 15. The piezo audion may be employed equally Well as an emitter of sound vibrations. The electrodes 10 and 12 acquire related piezo electric charges which are directly impressed upon the input circuit of the electron discharge device for. correspondingly controlling the current in the output circuit. The apparatus of my invention has a high electrical el'ficienc by virtue of the extremely close relations ip of the piezo electric device and the elements of the electron discharge device.

I have described my invention in one of its preferred embodiments, but I desire that it be understood that modifications may be made and that no limitations upon my invention are intended other than are imposed by the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is 'as follows:

1. A piezo audion comprising an evacuated vessel, a plurality of electrodes'within said vessel and an element possessing piezo electric properties electricall connected with at least one ofsaid electr es said element being positioned in alignment with the axis of said electron tube and connected mechanically with one wall thereof for impressing sound vibrations incident upon the envelope of said evacuated vessel upon said piezo electric element for setting up of piezo electric charges in proportion to the amplitude of sound vibrations incident upon said evacuated vessel and transferring said charges to at least one of said electrodes within said vessel. 7

2. A piezo audion comprising an evacuated vessel, a plurality of electrodes within said vessel, a piezo electric element supported adjacent to said electrodes, said piezo electric element being mechanically connected with one wall of said vessel for receiving mechanical stresses due to sound vibrations incident upon the exterior wall of said evacuated vessel for the generation of electrical charges and connections between said element and certain of said electrodes said elecand filament electrodes whereby sound vi brations incident upon the wall of said evacuated vessel operate to set up piezo electric charges which are impressed upon said grid and filament electrodes.

4. .A piezo audion comprising an evacuated vessel, grid, filament and plate electrodes, a support on which said electrodes are mounted within said vessel, 9. contact member carried by said support, a contact member secured on one wall of said evacuated vessel and an element possessing piezo electric properties disposed between said contacts, connections between said contacts and said grid and filament electrodes whereby sound vibrations incident upon said evacuated vessel operate to introduce stresses in said piezo electric element for setting u electrical charges and impressing sai charges upon said electrodes.

5. A piezo audion comprising in combination an evacuated vessel, a thermionic electrode, a control electrode, a plate associated therewith, and a piezo electric element arranged within said evacuated vessel .in axial alignment with said electrodes and connected with the wall of said vessel for receiving increment forces of sound waves incident upon said vessel and subjecting said element to mechanical stresses for setting up electrical charges and connections between said element and certain of said electrodes for impressing said charges upon said electrodes in proportion to the amplitude of said sound vibrations.

6. A piezo audion comprising an evacuated vessel, a plurality of electrodes, a centrally extending support for said electrodes and a piezo electric device mounted between the extremity of said support and one wall of said evacuated vessel and connected to certain of said electrodes whereby sound vibrations incident upon the exterior of said evacuated vessel operate to impress electrical charges from said piezo electric device upon said electrodes.

7. A piezo audion comprising an evacuated vessel, grid, filament and plate electrodes disosed within said vessel, a centrally extendlng support for said electrodes, said centrally extending support having a contact on the extremity thereof, a contact carried by one wall of said evacuated vessel in alignment with said centrally extending support, a piezo electric device mounted between said contacts and connections between said contacts and certain of said electrodes whereby sound vibrations incident the exterior of said evacuated vessel subjects said piezo electric device to stresses for delivering electrical charges to said contacts and to said electrodes.

waves incident upon said diaphragm subject said piezo electric device to mechanical stresses for setting up charges thGIGIIIJfO'I impression upon said electrodes within said vessel.

9.. Electrical apparatus comprising an evacuated envelope, grid filament and plate electrodes disposed within said envelope, a piezo electric crystal element having a pair of terminals and means for supporting said piezo electric crystal element at the terminals thereof between one wall of said evacuated envelope and said aforementioned grid filament and plate electrodes.

l0. Electr ical apparatus comprising an evacuated envelope, grid filament and plate. electrodes disposed within said envelope a piezo electric crystal element, c0nduct1ve coatings secured to the opposite faces of said piezogelectric crystal element, said conductive coatings independently terminating at opposite ends of said piezo electric crystal element and being substantially insulated from each other, and means for supporting said piezo electric crystal element between one wall of said evacuated vessel and said grid filament and plate electrodes.

Intestimonv whereof I \aflix my signature.

ALEXANDER McLEAN NIC OLSON. 

